In situ reversible tuning of chemical interface damping in mesoporous silica-coated gold nanorods via direct adsorption and removal of thiol

Abstract

Chemical interface damping (CID) is a recently proposed plasmon decay channel in gold nanoparticles. However, thus far, a very limited number of studies have focused on controlling CID in single gold nanoparticles. Herein, we describe a new simple method for reversible tuning of CID in single gold nanorods coated with a mesoporous silica shell (AuNRs@mSiO₂). We used 1-alkanethiols with two different carbon chain lengths (1-butanethiol and 1-decanethiol) as adsorbates to induce CID. In addition, NaBH₄ solution was used to remove the attached thiol from the AuNR surface. We confirmed the adsorption and removal of 1-alkanethiols on single AuNRs@mSiO₂ and the corresponding changes in localized surface plasmon resonance (LSPR) peak wavelengths and linewidths. Furthermore, we investigated the effect of immersion time in NaBH₄ solution on thiol removal from AuNRs@mSiO₂. Therefore, the LSPR properties and CID can be controlled, thereby paving the way for in situ reversible tuning of CID by repeated adsorption and desorption of thiol molecules on single AuNRs@mSiO₂.